AA2004 LAX to ORD Landing Gear... On my 4th of 5 DEQMs today and once again, a landing gear issue on AA. We lifted off over the blue Pacific on an ubelievably clear day. The gear retracted, but from the sound reverberating into the aircraft. Rob760 from FT and I were discussing the issue when the pilot made a right turn (usually a left hand departure) then a sharp left and seemed to be lining up for the pattern as we flew North of LAX. The gear then extended and retracted and seemed to be fine. The pilot then announced the nose gear door had remained open and after cycling the gear it was closed. He also said "we are now on our way to Chicago" so I am assuming the abnormal take off pattern was due to the gear door issue. This is now the second time in less than a week I have been on an AA flight with gear issues. Let's hope this is just a coincidence and not a result of the current status of AA!